1. Field of the Invention
The present invention relates to a flexure that supports a read-write head and to a head suspension with the flexure, the head suspension with the flexure and read-write head being used to write and read data to and from a magnetic disk in a magnetic disk drive or hard disk drive.
2. Description of Related Art
In a magnetic disk drive or hard disk drive, the read-write head supported with a head suspension slightly floats from a surface of a magnetic disk driven at high speed and writes/reads data to/from the magnetic disk. Examples of the head suspension are disclosed in, for example, Japanese Unexamined Patent Application Publications No. 2003-031915 and No. 2007-287280 in which the head suspension supports the read-write head with a flexure.
The flexure includes a metal base plate, an insulating layer formed on the metal base plate, and a wiring pattern formed on the insulating layer. A first end of the wiring pattern is connected to the read-write head and a second end thereof is connected to a plurality of terminals for external connection. The terminals are connected to terminals of a circuit board of the magnetic disk drive, to establish electrical connection between the read-write head and the circuit board.
Recent magnetic disk drives or hard disk drives are required to reduce power consumption and improve operating speed. For this, it is very important to correctly measure and evaluate electrical characteristics of the flexure.
To measure and evaluate the electrical characteristics of a flexure, TDR (time domain reflectometry) is used for measuring a characteristic impedance of the flexure, or S-parameters are used for testing a transmission loss of the flexure.
To correctly carry out the electrical characteristics evaluation, a measuring device used for the evaluation must correctly be calibrated at an impedance of 50Ω and the calibrated state must be maintained.
In addition, the measuring device, which is provided with a signal probe and a ground probe, must secure a fixed probe distance between the signal probe and the ground probe. The probe distance must be within about 350 micrometers (μm) when measuring GHz-order high frequencies transmitted through the flexure.
Due to such a short probe distance, the flexure must secure a contact point for the ground probe in the vicinity of a terminal serving as a contact point for the signal probe.
Flexures according to related arts have no consideration on the contact point for the ground probe, and therefore, an insulating layer of a flexure sampled for an electrical characteristics evaluation must be removed in the vicinity of a terminal of the flexure, to expose a metal base plate of the flexure for a contact point of the ground probe.
The removal of the insulating layer of the flexure deteriorates workability of the electrical characteristics evaluation and roughens the surface of the contact point for the ground probe to shorten the service life of the ground probe of the measuring device that is expensive.